Rabble apparatus for furnaces



Sept. 18 1923.

l.. B. sKlNNER RABBLE APPARATUS FOR FURNACES Filed May 24, 1920 2v Sheets-Sheet 1 Sept.y 18 1923.

- L. B. SKINNER RABBLE APPmwrus FOR FuRNAcEs Filed May 24 1920 2 Sheets-Sheet 2` ilu l 'l Patented Sept. 18, 1923. I

l. UNITED sra-res LEWIS BAILEY SKINNEE, or DENVER, CoLoEADo.

for Furnaces; and I do hereby declare the following to be a Jfull, clear, andexact de,` scription of the invention, such as Willenable others skilled in 'the art to vWhich itrv appertainsto make and use thefsame.

for furnaces. More Yparticularly the in-Y vention relates to Va rabble construct-ion adayitedibr` use `in ore roasters of the type' commonly known' inthe'art'as the lllcou-` gall type. Such a roastcr comprises a plu` rality of f superposed circular vhearths or Y, shelves through which extendsaxially a ver-` tical shat't carrying radially disposed rabble arins equippedavith teeth or plot-vs which stir the vore on each hearth as the vertical rabble shaft is slowly'. revolved, Vand at the" saine time advance the ore `gradually dovvii i'roni .the top hearth to the hearth next below, and so on through the series, theoiei being moved alternately toward and from the central sha-ft over the #successive hearths by the rabble devices. l' f The MCDougall type of roaster -has been used extensively in roasting 'sultid vores,.but as the rabble arnis and teethnare subjected to severe operating conditions.l by reasonot the heat ot the furnacey and .the corrosive character of the sulfur gases, deterioration and destruction of the rabble'niechanismat a comparatively rapid rate ditlicult to' guard against andhas heretofore restricted the use of this type or" furnace to roastingoperations in which the rabble teeth or higher than a-clierry red heat. In practice, the rabble arms and teethV are runiversally inade of metal, usually castV iron, this mate-r 4 rial complying inost nearly with the requirements ot strength and durability'for structures ot' this kind. At suh'iciently high teinperatures, however, iron reacts readily with elemental sulfur and with sulfur gasesproduced in roasting sullid` oresfg'v and Vit such' temperatures are reached, the ldestruction ot" the rabble mechanism, is very rapid. Ifthe temperature ot' the rabble mechanism caribe kept beloiv such destructive temperatures', the mechanism4 Will"last a comparatively long time, the only destructive factor billgV BABELE APPARATUS 'EOE 'rUENacEs plows are not subjected to temperatures iippiication ined May 24', 1920. serial Noleeaeia l the relatively slovvrinechanicalWear on :the

heavy metalI castings. -As the tooth or plow devices are theV parts subjected to they great# est amount ofwvear and `tearin actual'serv-- ice, it 'has VAbeen found. highly desirable thatn they be constructed as separate units-and' det'achablyf secured to the 'rabble farms, Aso that they'can be quickly and easily replaced',

Wheiiworn out or broken. :In order'toprdv long-the lite ofthe-rabble mechanism, itis.

for internally coolingthe rabble arm proper,` but'.y Yso far as y am aware, no practical, method of cooling: the rabble teeth or ploivs` l K Y common practice in the artto provide means This invention relates to rabble apparatus theinselveshas been lrnoyvnlheretofore, espe-1 Y ciallywhere. theteethA are detachable. Inv

actual operation' the Arabble-teeth are einbeddedinthe ore in the hearth, and the tern'-l Aigieraturein theV inassof ore is substantially higher than that in thespacebetween any tivo heart-hs or that` indicated 'by a pyroineter placed abovetlie rabble arm.V Asa result, thel ypractical application vof roasting .furnaces ofthe; type .in vquestion has beeny lstrictly `limited to roasting Voperations-iii which the'jrnaxiinuni.hearth temperature -re-y A quired, andv hence 'the temperature of the i uncooled rabble teeth or plows themselves,

can be kept down'substantially toa cherry. red lie-at or lower; VOperation at substan! tially higher temperatures has been out of the question becauseo't' the resultantfrapid destruction ofthe rabble teeth.V

In 'certain classes oitfroasting operations,; a' roasting temperature very' much higherl than Ythat for which the' McDougall type oi"- roaster has been adapted heretoforeV isre- `quired. "For example, the roasting voi Zinc oresY tor .the retort distillation processes deniaiids suclia high temperature to 'break Y downthezsultates and to keep the fault-71Y sulturdeivn bel'ou'Y lper cent, that allI attempts heretofore to utilize 'the very desirable YMcDougall type of roaster have resulted in failure'. rllhe .inability "of 'thev uncooledj cast iron rabble teeth to resist the suliidini;V action at .high temperatures has lpreventecl the application; of such 'roast-erste the "desulfurizing ot' blende, andtheabsence of any practical'nietliod of cool-ing'the ,teethV has made it impossible heretofore to get around this difficulty. 'Y As a result, Siti has beenl neeessarytoresort to the use efiothcr and j less desirable types of roasters, such as 'the `Well known Hegelerkilm for desulfurizing zincbleiide. Ascompared to the McDougall type of roaster, the only roastei's yhereto fore applicable in practice for desulfurizing blende, involve far greater initial investment for apparatus and auxiliary vequipinent, occupy much larger ground space, require more and higher` priced laborV to operate, and consume much more power and fuel. of the gas produced is not uniform, ranging more or less erratically from' per cent to 5 per centyivhereas a McDougall type furnace, such vas .that disclosed in my prior patent No..1,16l,130, for example, producesV a uniform gas running about 7% per cent sulfur dioXid. t Y

Oneof the principal objects of the present invention is therefore to provide a rabble structure -of which not only the rabble lying the invention.

arm but the teeth or ploivs ean'bc internally cooled and thereby kept beloiiv destructive temperatures eventhough the hearth teinperature of the roaster be very i'iiucli above the maximum heretoforefperniissible in the use of such rabble devices, and thus to make' it possible to employ roasters of the McDou-y gall or Skinner'type for desulfurizing zinc blende or for other roasting operations necessitating hearth temperatures substantially above a, cherry red heat. Y

lith the above Ygeneral object in vien',

and some others Which Will appear from the description hereinafter, the invention consists in the features, details of construction Yand combination of parts which will firstV be described in connection with the'ac'coinpanying drawings and then more particu-` larly pointed out.

lVhile the invention is not limited in its application to rabble adapted for use in roasters of the McDougall or .Skinner type, such va rabble construction Will be hereinafter: described as an illusv trative embodiment of the principles under- An especially` desirable practicalembodiment of the invention, adapted for employment in a roasting Y furnace of the type disclosed in my prior U. S. Patent No. 1,164,130, is for example illustrated in the accoinpanying drawings, in which Figs. 1 and 2 are a side elevation and plan,

respectively, partly broken avvay and in sec.-y

tion, showing the novel rabble; structure mounted in position on the vertical rabble shaft of the furnace; Y

' Figs. 8 and, L are a plan Yand side elevation, respectively, of the Skelton supporting member or arm, upon which the hubs of therabble teeth or rakes are mounted, the socket ends of' said arms being shownin longitudinal section;

Figs. 5, 6 and 7, are cross-sections taken. respectively, ,on the lines 575, tif-.6, of 2, and Te-.7 of Figs. 2 and 3;- and Fig. 8 iis a4 planet one .0f the rabble Moreover, the sulfur dioxid contentY constructionsv tooth devices, .the hub portion thereof being shown in horizontal sect-ion on the Iline 8-8 of Fig. 5.

Referring to thedraivings, A represents the revoluble vertical rabble shaft of a roasting furnace, While B represents generally the complete rabble arm structure mounted in place on the vertical rabble shaft A in a manner to be hereinafter described. The vertical rabble shaft is divided into vtvvo .conduits 11 and 12 for inflow and outflow of aA cooling medium such as air, for ci;- ample. The rabble arin .structure is pro-i vided with a 'hollow cylindrical socket end 13, Which may be slightly tapered to fit. into a socket 14 provided in .the shaft In order -to secure the rabble arminproperr position, the socketend `13 is provided with a locking lug 15, adapted Yto pass ythrough a slot 16 provided in the rim ait-the entrance of the socket 14, and to vengage the sloping inner edge of ai locking shoulder or cani surface 11'? provided in another location on the inner wall of said socket,'-Whereby the socket end 13 can be thrust into the socket and then given a 900 turn to engage lug 15 behind shoulder 17 and draw the .end ofthe rabble struct-ure into the socket. A stopKV shoulder 18 ispiovided onv theY innerivall of vthe socket 'to prevent further turning movement of the rabble .arm when the parts have been brought into proper position. The arrangement thus farA described is substair tially that .disclosed Ain my prior .patent aforesaid. 1 Y v- The cylindrical or enclosed portion ofthe arm or Y tooth-supportingineinber' proper terminates at the shoulder 19, the outer vertical face of which is accurately machined to present a plane bearing surface. Anothershoulder. or flange `2O :abuts against 'the an-x tion 10, forming in effect a continuation l thereof. As clearly shown in Figs. 3 and a, said partition Wall 22 continues as a vertical Web 23 beyond the cylindrical socket endlof the skeleton supporting arm propenterrninating at 24 adjacent the ein treme outer end thereof- In the present.

construct-ion the vertical web 23 is intelsected niedially by a horizontal bale and stiifeningweb 25 which does not extend the full length of the supporting arm and which in this iii-Stance has its inne-r end 2.6 acljacent the shoulder 18- itS- Guter and. at

Yappear later;

27, where it terminates somewhat short 'of the outer end V24`of the vertical partition.

While this horizontal partition is not anl indispensable feature of the invention in its broader aspects, it is nevertheless 'highly advantageousv as will hereinafter appear. The Vskeleton ed tip or stud .28, the purpose of which will Each ofthe rabble tooth or rakel devices assembled with Ythe skeleton supporting membern to formthe completefrabble apparatus of the invention comprisesv a' cylindricalY hub portion 29VA anda toothor blade portion-30 cast integralfther'et'vith.l The hub'- portionV 29A is'provided..at'its'ends with flanges 31, .theend facesv of which are acfcurately machinedto form tight joints with the end facesof cooperating hubs or sleeves 29 assembled therewith. lTheV form of theV joint b etweeiithe abutting 'faoes, ofxthese flanges may be of any suitable character that.

will servevto provide'l a close fitting joint adapted to prevent 'substantial v`leakage of cooling mediumtherethrough. `ln thel parj ticular construction illustrated, the abutting faces 'of' said flanges 31 are plane, butrother suitable forinsfor said faces are not eX- cluded. j The inner'walls of the hub members 29 are provided with longitudinal keyways 32ada-pted'to receive the outer edgesof the webs 23', 25, turning movement of the hubs onV the webbed supporting `memberV being vthus prevented. 4The series ofrabble tooth devices or rakes may thus be strung in posi# tionv on the skeleton vsupporting arm pushing the hub portionsf29` on over the outer end` of said .supportingv member one after the other, and then clampingthe vwhole series tightly in position against the flange 19 by means of a closure cap 33 which is in-VV ternally threaded to engage thepthreadedtip 28 and which is providedwith a wrench face whereby it Amay be turned up solid Vagainst the outer end of the series. rlhe inner face of the cap 33 is plane andadapted to make a tightjoint with the abutting face 3l of the adjacent tooth hub; and the arrangement is preferably such'that'the inner face of said cap lies close to or substantially abuts the Yedge 24 of web 23 when the cap is in place.

The assembled series oftoothl hubs an'd closure cap therefore form in effect a hollow or tubular rabble arm enclosing the skeleton supporting member from the shoulder 19 outward.` It will be seenthat Ythe vertical web 23 of said' supporting member dividesV the'ho'llow rabble arm construction centrally toprovide separate passages or lducts 34 and 35 on opposite sides thereoiand thateach of'said passages 34, 35, ish'orizontally di-V Y vided by the transverse web 25 into upper supporting member" thusV formed bythe intersecting webs characterizing the, present illustrative embodimentV of the invention mayterminate in a thread'- and lower :portions communicating only 'at ythe 'opposite ends 26, '27, of'said web 25.`

Each ofthe teeth or plows 30 is hollow or interiorly recessed as at '36, such recess eX-.

tending transversely, vin this linstance obliquely, below and across the center line of the rabble arm device, and opening into the lower half of both theV aforesaid conduits 34,

35,' within the rabble'arm. In other words,

the recesses or passages 36, afford aplurality of ,transverse parallel connecting passages between'the longitudinal inflow and Aoutflow passages Vor conduits 34 and 35, so"that cool-V Y ing medium supplied, say, from conduit 'l1 of therabble sha'ftlO may pass into conduit i 34 ofthe? rabble arm, thence'rthrou'gh pas? sages*36 into*L conduit 35, and thence into passage l2 of the rabble shaft, VThe vpro- 'vision of the`v cross-web "25 not only lends `mechanical strength and? stiiness to the con-V structionY butY it Vtends to eect Y uniform distribution of the cooling mediumrto the teeth. V'Cool Aair entering duct 34 rfrom thefrabble Y, shaft -will jflow both above and belo'wvthe horizontal 'partition 25,-that owing above so being compelled to-passl to the outer` endv of y the arm,fthusf ensuring a supply tothe outf ermost teeth.. In the absence of the horizontal baffle, there would be some tendency YtofavorY the teeth nearest shaft/A,'because they afford-theshortest pathV of travel 'for the'air.'

It will, be understood that apluralityjof' the described rabble structures may be mounted in Vpairs on opposite'sides of the vertical shaft- 10, as shown V'in luy-aforesaid prior ino 'patenhforexampla and that, owing to the tudi'nal passages' 34, 35, may serve as the inflow; passage or the outflow passage, in-A arrangement ofthe Vparts, eachY ofthel longii differently. I Whileonly one type of rake ,or

toothis here shown, say a .push inftooth,

Yit isobviousthat .push out7 teeth, oblique Throughout theforegoing specification,` the terms teet h,rplows?"andrakes have llO Although a specific Vembodiment of the' l from the scope and v spirit of f been variously employed, in accordance with the customary'fusagesi of the termsin this Y art, to denote the structural elements, indicated by the numeral 30in the drawings of 'applicants illustrative embodiment of his invention, mounted on "the rabble arm and ,functioning tostirtheoie onthe hearth. TheV terms c"toothwor teeth Vwhere employed inV theappended claims are to be understood in` the like generic sense to include plows, rakes or the like functioning to stir the ore on the hearth.

3. ln a rabble structure, the combination,

with a Vsupporting body, and hollow teeth removably assembledtherewith and having,r portions (3o-operating therewith 'to provide parallel incoming and outgoing cooling rne-` diuni passages connected by the said hollow teeth whereby the 'teeth are cooled.

4. In a rabble structure, the combination, with a webbed supporting bedy,. of' teeth having hollow hubs kassembled end to end onY said supporting` body and cooperating therewith to form a hollow rabble interiorly divided into cooling passages.

ln a rabble structure, the combination, with a supporting body having intersecting webs, of hollow teeth removably assembled therewith and cri-operating with said webs to form cooling medium passages. 6. ln a rabble; structure, the-combinatioin vwiQh a supporting body having` intersecting` webs, ot hollow teeth keyed to said body b y lthe febs and cooperating therewith to forin'cooling medium passages.

7. In a rabble structure, the combination, with supporting body having a passaged socket and a portion consisting of intersecting webs, oi a plurality of tooth devices having hubs keyed to said body by the webs and co-operating therewith to forni cooling medium passages.V

8. ln a rabble structure, the combination, with a supporting body having intersectingJ webs, of a plurality of hollow teeth each comprising a cylindrical hub andv a hollow blade, the hubs being' assembled on the supporting body to form a closed cylinder having passagesY divided by the webs but connected through said teeth.

9. In a rabble structure, the combination, with a-supporting bodyfhaving a socket end divided interiorly into `passages byla partition and terminating in a shoulder, a web constituting a continuation of said partition beyond the shoulder, and an intersect- Aing baffle web extending intermediate the ends of the irst web, of hollow tee'theach comprising a cylindrical hub-and a hollow blade of which the interior opens inte said iaeaeie hub, the hubs being*k assembled en the supporting body to form a closed cylinder having parallel passages on opposite sideslof the first web, each such passage being lon- `ggfitudina-lly divided by said baille web.

10. In a rabble structure, the combination, with a supportingbody having' a passaged socket end and a portion comprising intersecting webs, ashoulder on the socket end,

and a plurality of hollow toothV units,

each comprising' afcylindrica'l hub portion,

mounted on such webbed portion, the hubs of said units hav-ing machined faces adaptedV to abut said shoulder andes-ch other to :torin close joints,1and a retaining,r disk engagingl the face of the end tooth unit.

11. In a rabble s'tructureythe combination,

with a'supperting member formed vby intery secting'webs of which one terminates short ci the other at both ends, saidmember be- 4 ing.,r formed -at one extremity Yto provide atubular socket end having" an Yinflow passage, and an ou'tflowfpassage separated by the longer web olaV plurality oit tooth units assembled .witi Ysaid supporting member.,

each unitfzcomprising-a hub portion andl a tooth or blade integraltherewith and provided with an internalcooling,r recess open.- ingFY into said hub,` said unitbeing' strung on said supporting memberfwithsaid hubs f vin'endto endabutment and with the cool? ing` recessses of said teeth tra'nsverselyfunderlying;` the, longer web andconnecting; the longitudinal passages formed on oppositie Vsides thereof as continria-tions.orn the .inflow and outflow passages in said lsocket end.`

12.l ln a rabble structure, the combination, f

with a rabble armV comprising1 separable units provided with inflowand outiiow cool.-

ing passages, of hollowgrabbl'e toothY means mounted thereonand Vvaffording communication between saidpassages.

13.151 rabble structure comprising a rabble .larin composed' ot separable units and teeth interiorly Vformed to provide passages i y iio for'conducting' a cooling medium into said arm, through said teeth, and out again through said arm. V 1

14. A tubular rabble arm coiupos'edot a skeleton supporting member and a plurality Y of sleeves mounted end to end directly thereon, the interior of said arm beine,` divided into longitudinallyextending passages having kwalls 'formed-by" said sleeves andr said iis skeletonsupporting member .for inflow andoutliow, respectively, of a coolingV medium, in combination` with rabble teeth carried by said'sleeves.v I

' 15. A tubular. rabble arm composed of a supporting member and a plurality of sleeves mounted endto end'pthereon, the interior of said arm being divided into longitudinally extending pasages for inflow and outllow, respectively, of aA `Cooling medium, 

